For the sauce:- put the pancetta and onion in a pan with the oil and chilli, and fry gently for about 4-5 minutes. Add the white wine and tomatoes and cook for a further 15–20 minutes, stirring occasionally.
Meanwhile, bring a large saucepan of lightly salted water to the boil, and cook the pasta until al dente. Strain the bucatini and mix with the sauce. Serve sprinkled generously with the freshly grated pecorino.